title: The effect of a patellar brace on three-dimensional patellar kinematics in patients with lateral patellofemoral osteoarthritis.
abstract: OBJECTIVE
  Patellar bracing is a mechanical treatment strategy for patellofemoral osteoarthritis (OA) that aims to unload the lateral compartment of the joint by translating the patella medially. Our objective was to determine whether a patellar brace can correct patellar kinematics in patients with patellofemoral OA.
  
  
  METHODS
  We assessed the effect of a patellar brace on three-dimensional patellar kinematics (flexion, spin and tilt; proximal, lateral and anterior translation) at sequential, static knee postures, using a validated magnetic resonance imaging (MRI)-based method, in 19 patients with radiographic lateral patellofemoral OA. Differences in kinematics between unbraced and braced conditions were assessed in the unloaded and loaded knee (15% bodyweight load) using hierarchical linear random-effects models. Random slope and quadratic terms were included in the model when significant (P<0.05).
  
  
  RESULTS
  Bracing with load caused the patellae to translate 0.46 mm medially (P<0.001), tilt 1.17° medially (P<0.001), spin 0.62° externally (P=0.012) and translate 1.09 mm distally (P<0.001) and 0.47 mm anteriorly (P<0.001) over the range of knee flexion angles studied. Bracing also caused the patellae to extend in early angles of knee flexion (P<0.001). The brace caused similar trends for the unloaded condition, though magnitudes of the changes varied.
  
  
  CONCLUSIONS
  Bracing changed patellar kinematics, but these changes did not appear large enough to be clinically meaningful because no reduction in pain was observed in the parent study.
authors.affiliation: Department of Mechanical Engineering, University of British Columbia, Canada.
authors.forename: E J
authors.initials: EJ
authors.lastname: McWalter
authors.forename: D J
authors.initials: DJ
authors.lastname: Hunter
authors.forename: W F
authors.initials: WF
authors.lastname: Harvey
authors.forename: P
authors.initials: P
authors.lastname: McCree
authors.forename: K A
authors.initials: KA
authors.lastname: Hirko
authors.forename: D T
authors.initials: DT
authors.lastname: Felson
authors.forename: D R
authors.initials: DR
authors.lastname: Wilson
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D001915:Braces; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000503:physiopathology* / Q000628:therapy*; D010329:Patella / Q000503:physiopathology; D057071:Patellofemoral Joint / Q000503:physiopathology*